#include<bits/stdc++.h>

#define endl "\n"
// #define int long long

using namespace std;

using i64 = long long;
using u64 = unsigned long long;

constexpr int N = 500, M = 2e6 + 10;
constexpr int P = 998244353;
constexpr int INF = 1e9;

void solve() {
    int n, m, k, w;
    cin >> n >> m >> k >> w;
    //1 red 2 black
    vector<array<int, 2>> block;
    for (int i = 0; i < n; i++) {
        int x;
        cin >> x;
        block.push_back({x, 1});
    }
    for (int i = 0; i < m; i++) {
        int x;
        cin >> x;
        block.push_back({x, 2});
    }
    block.push_back({0, 2});
    block.push_back({w + 1, 2});
    sort(block.begin(), block.end());
    vector<int> black;
    for (int i = 0; i < block.size(); i++) {
        if (block[i][1] == 2) {
            black.push_back(i);
        }
    }
    vector<int> op;
    for (int i = 0; i < black.size() - 1; i++) {
        int R = block[black[i + 1]][0];
        int L = block[black[i]][0];
        int l = black[i] + 1, r = black[i + 1] - 1;
        vector<int> temp;
        int preL = -1;
        int j = l;
        while (j <= r) {
            auto pos = block[j][0];
            if (preL == -1) {
                if (pos + k - 1 >= R) {
                    preL = R - k;
                } else {
                    preL = pos;
                }
                if (preL <= L) {
                    cout << -1 << endl;
                    return;
                }
                temp.push_back(preL);
            } else {
                if (preL + k - 1 < pos) {
                    preL = pos;
                    temp.push_back(preL);
                    if (preL + k - 1 >= R) {
                        int dis = preL + k - 1 - R + 1;
                        int sub = dis;
                        for (int j = temp.size() - 2; j >= 0 && dis > 0; j--) {
                            int fx = temp[j + 1] - (temp[j] + k - 1) - 1;
                            if (fx >= dis) {
                                fx = dis;
                            }
                            temp[j + 1] -= sub;
                            dis -= fx;
                        }
                        if (dis > 0) {
                            cout << -1 << endl;
                            return;
                        }
                    }
                }
            }
            j++;
        }
        op.insert(op.end(), temp.begin(), temp.end());
    }
    cout << op.size() << endl;
    for (auto item : op) {
        cout << item << " ";
    }
    cout << endl;
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    int T;
    cin >> T;
    while (T--) {
        solve();
    }
}